I have the complete National Elevation Dataset from USGS in over 3000 ArcGrid files (coming to almost 190 GB), and a polygon shapefile of Colorado counties. I'm trying to use ArcMap Zonal Statistics to get the mean elevation for every county in Colorado, but after hours of processing, it repeatedly errors out. Is the mosaic just too big to work with?

I've tried Raster Calculator (to go from float to int) and Mosaic To New Raster, but both have failed.

  • Try to convert polygons to grid, set processing extent and cell size equal to it
    – FelixIP
    Mar 23, 2016 at 17:51

1 Answer 1


To reduce the size of my project, I used Model Builder to iterate through all my tiles, and save them as integers (they were floats; this question was helpful). Then, I made a new mosaic out of these int tiles. This made a huge difference; Zonal Statistics to Table worked.

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